1. Field of the Invention
The present disclosure relates to a synchronizer for a transmission.
2. Discussion of the Background
This type of synchronizer for a transmission generally includes a hub that is fixed to a rotating shaft and that has a plurality of spline teeth on an outer periphery thereof, a sleeve that has a plurality of spline teeth on an inner periphery thereof and that is splined to the hub, and a blocking ring that has spline teeth on an outer periphery thereof and that has a conical surface that engages with a conical surface of the gear. To set a gear position, the sleeve is driven by a shift rail so that the blocking ring is pushed toward the gear. Accordingly, the conical surfaces of the blocking ring and the gear come into contact with each other so that a frictional force is generated which synchronizes the gear with the rotating shaft. In this state, the spline teeth of the sleeve mesh with the spline teeth of the blocking ring and dog teeth of the gear, thereby a gear position is set.
In such a synchronizer, in the case where the gear has a small diameter and meshes with another gear, an end of the sleeve moved to synchronize the gear with the rotating shaft may come into contact with a side surface of the other gear. In such a case, if there is a differential rotation between the gears, there is a risk that contact portions of the sleeve and the other gear will wear unevenly or become damaged.
Japanese Patent No. 2724742, for example, discloses a synchronizer including a sleeve that is provided with a stopper that regulates the movement thereof to solve the above-described problem. The synchronizer includes a retaining portion that is formed integrally with gear-side end portions of two adjacent spline teeth of a hub so as to connect the end portions. The spline tooth of the sleeve that corresponds to the retaining portion is cut so that only an end portion at the end opposite the retaining portion remains, and the remaining end portion serves as an engagement portion. When the sleeve moves toward the gear, the engagement portion of the sleeve comes into contact with the retaining portion of the hub so that the movement of the sleeve is stopped and the above-described problem does not occur.